X-plane

Bell X-1

The X-planes are a series of experimental United States aircraft (and some rockets) used for testing of new technologies and usually kept highly secret during development.

The first of these, the Bell X-1, became well-known as the first plane to break the sound barrier, which it did in 1947. Later X-planes yielded important research results, but only the North American X-15 rocket plane of the early 1960s achieved comparable fame. X-planes 7 through 12 were actually missiles, and some other vehicles were unpiloted. Most X-planes are not expected to ever go into full-scale production, and usually only a few are produced. One exception is the Lockheed Martin X-35, which competed against the Boeing X-32 to become the Joint Strike Fighter.

As of 2006, new X-plane projects are still underway. The designation X-52 was skipped to avoid potential confusion with the operational B-52 Stratofortress strategic bomber.

List of X-planes

Name	Manufacturer	Image	Maiden flight	Notes
X-1	Bell Aircraft		January 19, 1946	First aircraft to break the sound barrier
X-2 Starbuster	Bell Aircraft		June 27, 1952	Supersonic plane Mach 2 - Mach 3
X-3 Stiletto	Douglas Aircraft Corporation		June 27, 1952	Supersonic plane using titanium alloy
X-4 Bantam	Northrop Corporation		December 15, 1948	Replace horizontal tail with elevons
X-5	Bell Aircraft		June 20, 1951	Variable-sweep wing design
X-6	Convair		Not flown	Study Nuclear aircraft
X-7 Flying Stove Pipe	Lockheed Corporation		April 1951	Test ramjet engines
X-8 Aerobee	Aerojet			Missile test platform
X-9 Shrike	Bell Aircraft		April 1949	Testbed for the nuclear-armed GAM-63 Rascal
X-10	North American Aviation		October 13, 1953	Demonstrator for advanced missile technologies
X-11	Convair		June 11, 1957	Testbed for the Atlas missile program
X-12	Convair		July, 1958	Advanced testbed for the Atlas missile program
X-13 Vertijet	Ryan Aeronautical Company		December 10, 1955	Demonstrate the ability of a pure jet to vertically takeoff, hover, transition to horizontal forward flight, and vertically land
X-14	Bell Aircraft		February 19, 1957	Demonstrate horizontal, vertical takeoff, hover, transition to forward flight, and vertical landing.
X-15	North American Aviation		June 8, 1959	Research hypersonic flight (Mach 6)
X-16	Bell Aircraft		Never flew	High altitude reconnaissance aircraft
X-17	Lockheed Corporation		April 1956	Effects of high mach reentry
X-18	Hiller Aircraft		November 24, 1959	Tiltwing and STOVL
X-19	Curtiss-Wright		November 1963	VTOL transport plane with Tiltrotor
X-20 Dyna-Soar	Boeing		Never flew	Reusable spaceplane for military missions
X-21	Northrop Corporation		April 18, 1963	Test wings with laminar flow control
X-22	Bell Aircraft		March 17, 1966	STOVL plane with tiltrotor
X-23 PRIME	Martin Marietta		December 21, 1966	Atmospheric reentry effects tests
X-24 PILOT	Martin Marietta		August 1, 1973	Lifting body plane
X-25 Bensen B-8	Bensen		December 6, 1955	Light autogyro
X-26 Frigate	Schweizer		1967	Motor glider
X-27	Lockheed		Never flew	High performance fighter prototype
X-28 Sea Skimmer	Periera		August 12, 1970	ULM sailboat
X-29	Grumman		1984	forward-swept wing test plane
X-30 NASP	Rockwell		Never built	Commercial spaceplane prototype
X-31	Rockwell		1990	Thrust vectoring fighter
X-32	Boeing		September 2000	Fighter both conventional, STOVL and marine
X-33 Venture Star	Lockheed Martin		Never ended Prototype	Reusable spaceplane
X-34	Orbital Sciences		Never flew	Reusable unmanned spaceplane
X-35 JSF	Lockheed Martin		2000	Fighter both conventional, STOVL and marine
X-36	McDonnell Douglas		May 17, 1997	Tailless aircraft
X-37 Future X	Boeing		April 7, 2006	Experimental orbital vehicle
X-38 CRV	NASA		1999	CRV (=Crew Return Vehicle) with lifting body
X-39	????	Classified	Not yet	FATE : Future Aircraft Technology Enhancements
X-40 SMV	Boeing		August 11, 1998	SMV=Space Maneuver Vehicle
X-41 Common Aero Vehicle	????	Classified		Reentry vehicle with commercial load
X-42	????	Classified		Liquid propellant military rocket
X-43	NASA		June 2, 2001	Scramjet hypersonic Drone
X-44 MANTA	Lockheed Martin		Prototype not completed	MANTA=Multi-Axis No-Tail Aircraft with thrust vectoring
X-45	Boeing		22/5/2002	Demonstrator of unmanned combat air vehicle (UCAV)
X-46	Boeing			X-45 marine version for an unmanned combat air vehicle
X-47 Pegasus	Grumman		February 23, 2003	Demonstrator of naval unmanned combat air vehicle (UCAV)
X-48	Boeing		July 20, 2007	Blended Wing Body (BWB) flying wing
X-49 Speedhawk	Piasecki Aircraft		July 29, 2007	Fast helicopter VDTP (Vectored Thrust Ducted Propeller)
X-50	Boeing		24 November 2003	Demonstrate the principle that a helicopter's rotor can be stopped in flight and act as a fixed wing
X-51 Waverider	Pratt & Whitney et Boeing		(Scheduled) 2009	Test Scramjet engines
X-52				# not used (to avoid confusion with Boeing B-52 Stratofortress)
X-53	Boeing Phantom Works		November 2002	AAW : Active Aeroelastic Wing
X-55A[1]	Lockheed Martin Skunk Works		June 2, 2009	Test molded composite fuselage and empennage[2]

In fiction

Many movies, television series and video games have featured fictional X planes, with both feasible and currently infeasible designs. For instance, the Stargate TV series feature X-301, X-302, X-303, and X-304 spacecraft. The movie Armageddon featured two top-secret space shuttles called X-71.

See also

• Experimental aircraft
• List of experimental aircraft
• List of military aircraft of the United States
• Skunk works
• Boeing Phantom Works

References

• Jay Miller, The X-Planes: X-1 to X-45. Motorbooks International, 2001.

External links

Wikimedia Commons has media related to: X-planes

• Early X-planes
• American X-Vehicles: An Inventory X-1 to X-50, SP-2000-4531 - June 2003; NASA online PDF Monograph
• X-15 Videos by NASA